A multimode base station refers to a base station that can simultaneously support multiple wireless standards. A common base station that can support both a Global System for Mobile communications (Global System for Mobile communications, GSM) standard and a Universal Mobile Telecommunications System (Universal Mobile Telecommunications System, UMTS) standard is called a GU dual-mode base station, a base station that can support both a GSM standard and a Long Term Evolution (Long Term Evolution, LTE) standard is called a GL dual-mode base station, and a base station that can support both a UMTS standard and an LTE standard is called a UL dual-mode base station.
In an actual application, main control boards of different standards are generally overlaid in a baseband unit (Base Band Unit, BBU) to form a multimode base station. Using a GU dual-mode macro base station shown in FIG. 1 as an example, a board of the GSM standard and a board of the UMTS standard may be overlaid in a single BBU, where the board of the GSM standard and the board of the UMTS standard each are connected to a common-mode radio frequency module through a common public radio interface (Common Public Radio Interface, CPRI), so as to form a GU dual-mode base station.
It is found in practice that because slots supported by a single BBU are limited, standards supported by the single BBU are limited. Generally, a single BBU can support only two boards, and therefore, a multimode base station supports few standards.